[Diltiazem in spontaneous angina: comparison with nifedipine and verapamil]

Sixteen patients with spontaneous angina were studied to assess the relative efficacy of diltiazem (D) at different doses [240 mg/day (D240) versus 360 mg/day (D360)], nifedipine (N: 120 mg/day), and verapamil (V: 480 mg/day), given according to a latin-square protocol. Of the 16 patients, 6 had ischemic attacks with ST elevation, 6 had ischemic attacks with ST depression, 4 showed ST elevation or ST depression in different ischemic attacks. All the patients underwent 24-hour Holter monitoring: at the beginning of the study; during the third day of treatment with D240, D360, N or V; after the withdrawal of each treatment. An atrioventricular block was observed in 2 patients during treatment with V, and in 1 patient during treatment with D240 and D360. In the remaining cases, D and V significantly (p less than 0,05) prolonged the PR interval (D240: + 18%; D360: + 16%; V: + 20%), and reduced the mean daily heart rate (D240: -9%; D360: -12%; V: -11%). The effects of D and V were statistically not different. All the treatments significantly reduced the frequency of the ischemic attacks (p less than 0,05) (D240: -79%; D360: -93%; N: -90%; V: -90%). In particular, D240 reduced by the same percentage (-79%) the frequency of ischemic attacks with ST elevation and ST depression, while D360 completely abolished ischemic attacks with ST elevation and reduced by 79% those with ST depression. Our results suggest that: diltiazem is highly effective in the treatment of spontaneous angina; the efficacy of 360 mg/day of diltiazem is equivalent to that of 120 mg/day of nifedipine and of 480 mg/day of verapamil.(ABSTRACT TRUNCATED AT 250 WORDS)